19.3 One can use the fact table called Returned_Items with 
attributes Product_Id, Time_Id. Market_Id, and Returned_Amt. The 
dimension tables can be the same as those in the book.

(You can invent anything that you think make sense!)

19.13 If we use the threshold of 0.5 we can find two rules:
	 Purchase_diapers -> Purchase_beer
	 Purchase_beer -> Purchase_diaper

(You should detail how you get these two rules.)